1. Field of the Invention
Embodiments of the present invention relate to a display device, and more particularly, to a display device to improve the picture quality by selectively applying a frame rate control data pattern set based on a gray scale difference between video data of previous frame and video data of present frame, and a method of driving the same.
2. Discussion of the Related Art
Generally, a liquid crystal display (LCD) device includes two display substrates respectively provided with pixel and common electrodes. A layer of a liquid crystal material having a dielectric anisotropy is formed between the two substrates.
The pixel electrodes are formed in an active matrix arrangement. Also, the pixel electrodes are respectively connected with switching elements, such as thin film transistors (TFT). Data voltages are sequentially applied line-by-line to the pixel electrodes. A common electrode is formed on the entire surface of the display substrate. A common voltage is applied to the common electrode. The liquid crystal layer provided between the pixel electrode and the common electrode forms a liquid crystal capacitor with the pixel and the common electrodes. The liquid crystal capacitor and the switching element connected with each other form a pixel unit.
The voltage applied to the pixel and common electrodes of the LCD device generates an electric field in the liquid crystal layer. The light transmittance through the liquid crystal layer is controlled by the intensity of electric field to display the desired image. When the electric field is applied in one direction to the liquid crystal layer for a long period of time, the displayed image may be degraded. The polarity of the data voltage is inverted frame-by-frame, line-by-line, or pixel by pixel to prevent degradation of the displayed image.
Red (R), green (G) and blue (B) video data are inputted to the LCD device. A signal controller of LCD device processes the R, G and B video data, and supplies the processed data to a data driver including a data driving integrated circuit (IC). The data driver selects an analog gray scale voltage corresponding to the supplied video data, and applies the selected analog gray scale voltage to the LCD panel.
The number of bits in the video data inputted to the signal controller is identical to the number of bits processed by the data driver. The processing capability of the data driver is generally kept low to lower the manufacturing cost of the LCD device. For example, if the signal controller provides 8-bit R, G, and B video data, a 6-bit data driver can be used to lower the manufacturing cost.
A frame rate control (FRC) technology has been proposed for interfacing the signal controller with the data driver. However, the related art display device maintains a constant FRC data pattern without regard to the gray scale difference of video data. Accordingly, the picture quality deteriorates.